Playing with Pictures 90 The Alphabet Soup of Picture File Formats There's certainly no shortage of ways that the world's computer geeks have come up with over the years to confuse users and other mere mortals. But few things get the man-or-woman-on-the-street more thoroughly bamboozled than the bewildering array of file formats (also known as file types) that exist in the digital world. And perhaps the worst culprit is the picture file category, which boasts an unseemly large number of formats. My goal in this section is to help you get through the thicket of acronyms and minutiae that characterize picture file formats, and to show you how to simplify things so that they actually make sense. Before you go any further into this file format business, you might enjoy taking a step or two in reverse to consider the bigger picture: What is a file format and why do we need so many of them? I like to look at file formats as the underlying structure of a file that's akin to a car's underlying structure. The latter is a collection of metal and plastic bits that form the frame, axles, suspension, engine, and other innards that determine how the car performs. A file format is similar in that it consists of a collection of bits and bytes that determines how the picture is viewed. As you'll see, some formats are better suited for displaying photos, while others have a better time with line draw- ings. Windows Wisdom Throughout this chapter and in other parts of the book I'll use the terms picture, image , and graphic inter- changeably. The sigh-of-relief-inducing news is that even though the computing world is on speaking terms with dozens of different image formats, Windows XP is conversant with only five: · Bitmap--This is the standard image file format used by Windows XP. It's good for color drawings, although its files tend to be on the large side. Bitmap image files use the .bmp extension, so these files are also referred to sometimes as BMP files. · GIF--This is one of the standard graphics file formats used on the Internet's World Wide Web. It's only capable of storing 256 colors, so it's only suitable for relatively simple line drawings or for images that use only a few colors. The resulting files are compressed, so they end up quite a bit smaller than bitmap files. · JPEG--This is the other standard graphics file format that you see on the World Wide Web. This format can reproduce millions of colors, so it's suitable for photographs and other high-quality images. JPEG stores images in a compressed format, so it can knock high-quality images down to a manageable size while still retaining some picture fidelity. (However, the more you compress the image, the poorer the image quality becomes.)